An apple a day puts insects in your tummy
They say you need to eat more fruits and vegetables. We don’t know who they are (doctors?), but you’ve heard the saying before. However, they forgot to mention that you should wash your apple with water before biting down on the delicious fruit.
Right before the OP sunk their teeth into this Granny Smith apple, they found a weird growth right on the surface. Before tossing the apple away and washing their hands seven times, they asked the internet what the growth might be. Apparently, the OP was right to toss the entire thing away. Those were the eggs of a lacewing, an insect that feeds on fruits and nectar.